drivers/rtc/rtc-stmp3xxx.c

   1 /*
   2  * Freescale STMP37XX/STMP378X Real Time Clock driver
   3  *
   4  * Copyright (c) 2007 Sigmatel, Inc.
   5  * Peter Hartley, <peter.hartley@sigmatel.com>
   6  *
   7  * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
   8  * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
   9  * Copyright 2011 Wolfram Sang, Pengutronix e.K.
  10  */
  11
  12 /*
  13  * The code contained herein is licensed under the GNU General Public
  14  * License. You may obtain a copy of the GNU General Public License
  15  * Version 2 or later at the following locations:
  16  *
  17  * http://www.opensource.org/licenses/gpl-license.html
  18  * http://www.gnu.org/copyleft/gpl.html
  19  */
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/io.h>
  23 #include <linux/init.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/rtc.h>
  27 #include <linux/slab.h>
  28 #include <linux/of_device.h>
  29 #include <linux/of.h>
  30 #include <linux/stmp_device.h>
  31 #include <linux/stmp3xxx_rtc_wdt.h>
  32
  33 #include <mach/common.h>
  34
  35 #define STMP3XXX_RTC_CTRL                       0x0
  36 #define STMP3XXX_RTC_CTRL_SET                   0x4
  37 #define STMP3XXX_RTC_CTRL_CLR                   0x8
  38 #define STMP3XXX_RTC_CTRL_ALARM_IRQ_EN          0x00000001
  39 #define STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN        0x00000002
  40 #define STMP3XXX_RTC_CTRL_ALARM_IRQ             0x00000004
  41 #define STMP3XXX_RTC_CTRL_WATCHDOGEN            0x00000010
  42
  43 #define STMP3XXX_RTC_STAT                       0x10
  44 #define STMP3XXX_RTC_STAT_STALE_SHIFT           16
  45 #define STMP3XXX_RTC_STAT_RTC_PRESENT           0x80000000
  46
  47 #define STMP3XXX_RTC_SECONDS                    0x30
  48
  49 #define STMP3XXX_RTC_ALARM                      0x40
  50
  51 #define STMP3XXX_RTC_WATCHDOG                   0x50
  52
  53 #define STMP3XXX_RTC_PERSISTENT0                0x60
  54 #define STMP3XXX_RTC_PERSISTENT0_SET            0x64
  55 #define STMP3XXX_RTC_PERSISTENT0_CLR            0x68
  56 #define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN  0x00000002
  57 #define STMP3XXX_RTC_PERSISTENT0_ALARM_EN       0x00000004
  58 #define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE     0x00000080
  59
  60 #define STMP3XXX_RTC_PERSISTENT1                0x70
  61 /* missing bitmask in headers */
  62 #define STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER  0x80000000
  63
  64 struct stmp3xxx_rtc_data {
  65         struct rtc_device *rtc;
  66         void __iomem *io;
  67         int irq_alarm;
  68 };
  69
  70 #if IS_ENABLED(CONFIG_STMP3XXX_RTC_WATCHDOG)
  71 /**
  72  * stmp3xxx_wdt_set_timeout - configure the watchdog inside the STMP3xxx RTC
  73  * @dev: the parent device of the watchdog (= the RTC)
  74  * @timeout: the desired value for the timeout register of the watchdog.
  75  *           0 disables the watchdog
  76  *
  77  * The watchdog needs one register and two bits which are in the RTC domain.
  78  * To handle the resource conflict, the RTC driver will create another
  79  * platform_device for the watchdog driver as a child of the RTC device.
  80  * The watchdog driver is passed the below accessor function via platform_data
  81  * to configure the watchdog. Locking is not needed because accessing SET/CLR
  82  * registers is atomic.
  83  */
  84
  85 static void stmp3xxx_wdt_set_timeout(struct device *dev, u32 timeout)
  86 {
  87         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
  88
  89         if (timeout) {
  90                 writel(timeout, rtc_data->io + STMP3XXX_RTC_WATCHDOG);
  91                 writel(STMP3XXX_RTC_CTRL_WATCHDOGEN,
  92                        rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_SET);
  93                 writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER,
  94                        rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_SET);
  95         } else {
  96                 writel(STMP3XXX_RTC_CTRL_WATCHDOGEN,
  97                        rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR);
  98                 writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER,
  99                        rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_CLR);
 100         }
 101 }
 102
 103 static struct stmp3xxx_wdt_pdata wdt_pdata = {
 104         .wdt_set_timeout = stmp3xxx_wdt_set_timeout,
 105 };
 106
 107 static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
 108 {
 109         struct platform_device *wdt_pdev =
 110                 platform_device_alloc("stmp3xxx_rtc_wdt", rtc_pdev->id);
 111
 112         if (wdt_pdev) {
 113                 wdt_pdev->dev.parent = &rtc_pdev->dev;
 114                 wdt_pdev->dev.platform_data = &wdt_pdata;
 115                 platform_device_add(wdt_pdev);
 116         }
 117 }
 118 #else
 119 static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
 120 {
 121 }
 122 #endif /* CONFIG_STMP3XXX_RTC_WATCHDOG */
 123
 124 static void stmp3xxx_wait_time(struct stmp3xxx_rtc_data *rtc_data)
 125 {
 126         /*
 127          * The datasheet doesn't say which way round the
 128          * NEW_REGS/STALE_REGS bitfields go. In fact it's 0x1=P0,
 129          * 0x2=P1, .., 0x20=P5, 0x40=ALARM, 0x80=SECONDS
 130          */
 131         while (readl(rtc_data->io + STMP3XXX_RTC_STAT) &
 132                         (0x80 << STMP3XXX_RTC_STAT_STALE_SHIFT))
 133                 cpu_relax();
 134 }
 135
 136 /* Time read/write */
 137 static int stmp3xxx_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
 138 {
 139         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 140
 141         stmp3xxx_wait_time(rtc_data);
 142         rtc_time_to_tm(readl(rtc_data->io + STMP3XXX_RTC_SECONDS), rtc_tm);
 143         return 0;
 144 }
 145
 146 static int stmp3xxx_rtc_set_mmss(struct device *dev, unsigned long t)
 147 {
 148         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 149
 150         writel(t, rtc_data->io + STMP3XXX_RTC_SECONDS);
 151         stmp3xxx_wait_time(rtc_data);
 152         return 0;
 153 }
 154
 155 /* interrupt(s) handler */
 156 static irqreturn_t stmp3xxx_rtc_interrupt(int irq, void *dev_id)
 157 {
 158         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev_id);
 159         u32 status = readl(rtc_data->io + STMP3XXX_RTC_CTRL);
 160
 161         if (status & STMP3XXX_RTC_CTRL_ALARM_IRQ) {
 162                 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ,
 163                                 rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 164                 rtc_update_irq(rtc_data->rtc, 1, RTC_AF | RTC_IRQF);
 165                 return IRQ_HANDLED;
 166         }
 167
 168         return IRQ_NONE;
 169 }
 170
 171 static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled)
 172 {
 173         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 174
 175         if (enabled) {
 176                 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 177                                 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
 178                                 rtc_data->io + STMP3XXX_RTC_PERSISTENT0_SET);
 179                 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 180                                 rtc_data->io + STMP3XXX_RTC_CTRL_SET);
 181         } else {
 182                 writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 183                                 STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
 184                                 rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
 185                 writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 186                                 rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 187         }
 188         return 0;
 189 }
 190
 191 static int stmp3xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
 192 {
 193         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 194
 195         rtc_time_to_tm(readl(rtc_data->io + STMP3XXX_RTC_ALARM), &alm->time);
 196         return 0;
 197 }
 198
 199 static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 200 {
 201         unsigned long t;
 202         struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
 203
 204         rtc_tm_to_time(&alm->time, &t);
 205         writel(t, rtc_data->io + STMP3XXX_RTC_ALARM);
 206
 207         stmp3xxx_alarm_irq_enable(dev, alm->enabled);
 208
 209         return 0;
 210 }
 211
 212 static struct rtc_class_ops stmp3xxx_rtc_ops = {
 213         .alarm_irq_enable =
 214                           stmp3xxx_alarm_irq_enable,
 215         .read_time      = stmp3xxx_rtc_gettime,
 216         .set_mmss       = stmp3xxx_rtc_set_mmss,
 217         .read_alarm     = stmp3xxx_rtc_read_alarm,
 218         .set_alarm      = stmp3xxx_rtc_set_alarm,
 219 };
 220
 221 static int stmp3xxx_rtc_remove(struct platform_device *pdev)
 222 {
 223         struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(pdev);
 224
 225         if (!rtc_data)
 226                 return 0;
 227
 228         writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 229                         rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 230         free_irq(rtc_data->irq_alarm, &pdev->dev);
 231         rtc_device_unregister(rtc_data->rtc);
 232         platform_set_drvdata(pdev, NULL);
 233         iounmap(rtc_data->io);
 234         kfree(rtc_data);
 235
 236         return 0;
 237 }
 238
 239 static int stmp3xxx_rtc_probe(struct platform_device *pdev)
 240 {
 241         struct stmp3xxx_rtc_data *rtc_data;
 242         struct resource *r;
 243         int err;
 244
 245         rtc_data = kzalloc(sizeof *rtc_data, GFP_KERNEL);
 246         if (!rtc_data)
 247                 return -ENOMEM;
 248
 249         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 250         if (!r) {
 251                 dev_err(&pdev->dev, "failed to get resource\n");
 252                 err = -ENXIO;
 253                 goto out_free;
 254         }
 255
 256         rtc_data->io = ioremap(r->start, resource_size(r));
 257         if (!rtc_data->io) {
 258                 dev_err(&pdev->dev, "ioremap failed\n");
 259                 err = -EIO;
 260                 goto out_free;
 261         }
 262
 263         rtc_data->irq_alarm = platform_get_irq(pdev, 0);
 264
 265         if (!(readl(STMP3XXX_RTC_STAT + rtc_data->io) &
 266                         STMP3XXX_RTC_STAT_RTC_PRESENT)) {
 267                 dev_err(&pdev->dev, "no device onboard\n");
 268                 err = -ENODEV;
 269                 goto out_remap;
 270         }
 271
 272         platform_set_drvdata(pdev, rtc_data);
 273
 274         mxs_reset_block(rtc_data->io);
 275         writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 276                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
 277                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
 278                         rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
 279
 280         writel(STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN |
 281                         STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
 282                         rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
 283
 284         rtc_data->rtc = rtc_device_register(pdev->name, &pdev->dev,
 285                                 &stmp3xxx_rtc_ops, THIS_MODULE);
 286         if (IS_ERR(rtc_data->rtc)) {
 287                 err = PTR_ERR(rtc_data->rtc);
 288                 goto out_remap;
 289         }
 290
 291         err = request_irq(rtc_data->irq_alarm, stmp3xxx_rtc_interrupt, 0,
 292                         "RTC alarm", &pdev->dev);
 293         if (err) {
 294                 dev_err(&pdev->dev, "Cannot claim IRQ%d\n",
 295                         rtc_data->irq_alarm);
 296                 goto out_irq_alarm;
 297         }
 298
 299         stmp3xxx_wdt_register(pdev);
 300         return 0;
 301
 302 out_irq_alarm:
 303         rtc_device_unregister(rtc_data->rtc);
 304 out_remap:
 305         platform_set_drvdata(pdev, NULL);
 306         iounmap(rtc_data->io);
 307 out_free:
 308         kfree(rtc_data);
 309         return err;
 310 }
 311
 312 #ifdef CONFIG_PM
 313 static int stmp3xxx_rtc_suspend(struct platform_device *dev, pm_message_t state)
 314 {
 315         return 0;
 316 }
 317
 318 static int stmp3xxx_rtc_resume(struct platform_device *dev)
 319 {
 320         struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(dev);
 321
 322         mxs_reset_block(rtc_data->io);
 323         writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
 324                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
 325                         STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
 326                         rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
 327         return 0;
 328 }
 329 #else
 330 #define stmp3xxx_rtc_suspend    NULL
 331 #define stmp3xxx_rtc_resume     NULL
 332 #endif
 333
 334 static const struct of_device_id rtc_dt_ids[] = {
 335         { .compatible = "fsl,stmp3xxx-rtc", },
 336         { /* sentinel */ }
 337 };
 338 MODULE_DEVICE_TABLE(of, rtc_dt_ids);
 339
 340 static struct platform_driver stmp3xxx_rtcdrv = {
 341         .probe          = stmp3xxx_rtc_probe,
 342         .remove         = stmp3xxx_rtc_remove,
 343         .suspend        = stmp3xxx_rtc_suspend,
 344         .resume         = stmp3xxx_rtc_resume,
 345         .driver         = {
 346                 .name   = "stmp3xxx-rtc",
 347                 .owner  = THIS_MODULE,
 348                 .of_match_table = of_match_ptr(rtc_dt_ids),
 349         },
 350 };
 351
 352 module_platform_driver(stmp3xxx_rtcdrv);
 353
 354 MODULE_DESCRIPTION("STMP3xxx RTC Driver");
 355 MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com> and "
 356                 "Wolfram Sang <w.sang@pengutronix.de>");
 357 MODULE_LICENSE("GPL");